“The peaceful one is at war without and within.” —The Mantle, Fifth Permutation of the Didact’s Number

The Didact, born Shadow-of-Sundered-Star, [2] is a Forerunner Promethean who held an extremely high status in the Forerunner society as protector of the ecumene, [6] head of the Warrior-Servant rate and supreme commander of the entire Forerunner military. [7] He wholeheartedly believed in the Mantle the Forerunners held to protect life, and fervently opposed the Halo Array as a sin beyond measure. He was also the husband of the Librarian.

Originally thought to have been killed by the Master Builder, Faber, [8] the Didact effectively existed as two individuals during the final days of the Forerunner-Flood war; his original self, as well as his implanted consciousness within a young Forerunner known as Bornstellar Makes Eternal Lasting. To differentiate these two incarnations, the original Didact was referred to as the Ur-Didact, while his other incarnation was known as the IsoDidact. [9] The Ur-Didact was eventually exiled on Requiem, not to be awakened until 2557; [10] meanwhile, the IsoDidact served until the final days of the Flood conflict and was responsible for activating the Halo Array. [11] After facing Spartan John-117 and the rest of Blue Team, the Ur-Didact’s biological form was destroyed under the combined power of several Composers. While he is considered “contained” by the Office of Naval Intelligence, his digitized consciousness apparently survives. [1]